The \(A \leftrightarrow B\)  exchange symmetry of this model was used
in [1]}, [2]} to reduce
the recursion relations for moment ratios to a pair of self-consistent
solutions similar in form to those for the 1-species autocatalytic
CRN. The generator in the moment
representation (REF ) is a 2-dimensional
discrete Laplacian, given in Eq. (REF ). Its
solutions off the diagonal depend on boundary conditions at \(k_A = 0\) 
or \(k_B = 0\)  where the nonzero moment order need not lie in any
asymptotic regime. In the limit \(y_B \rightarrow 0\) , an estimate for
\(y_A\)  is given by
\(y_A =\frac{1}{{\hat{R}}_B}\left(\frac{{\kappa }_2 {\hat{R}}_A - \varepsilon }{{\kappa }_1 - {\bar{\kappa }}_1 {\hat{R}}_A}\right) -{\hat{R}}_A\) 
